Double Ball Arm Segments

An Ultralight arm generally consists of two arms segments and three clamps giving you the greatest flexibility. Videographers sometimes use just one arm segment and two clamps. They do not need the same amount of flexibility as a still photographer does.

The o-ring in the balls of the arms, base adapters, and strobe adapters eliminates the metal to metal contact. This allows a much more linear clamping force, allowing you to control the arm movement when used with small or large strobes even in varying current conditions.

The ball size of our arms and adapters is 1" or 25mm.

Example of two arm segments and three clamps

DB-03 - very short arm, look like small dumbells, used for macro photography

Single Ball Arm Segments

Allows you to use one less clamp in the arm set; but reduces flexibility at the strobe head

SBSS-5 - Single ball 5” arm with a Sea and Sea strobe adapter at the other end

SBSS-8 - Single ball 8” arm with a Sea and Sea strobe adapter at the other end

Original Buoyancy Double Ball Arm Segments

Original buoyancy double ball arm segments were designed for users of heavy cameras and housings. They are constructed of aluminum tubing with the ball ends press fit and glued in. Air trapped inside allows them to be buoyant.

DB-B16 - very long arm, used for super wide angle photography

DB-B12 - long arm, used for wide angle photography

DB-B08 - medium length use for macro or wide angle photography

Ultralight's 2" Buoyancy Arms

2.5 times more buoyant than the original buoyancy arms

Large Buoyancy double ball arm segments were designed for the heavy Digital SLR housings and video housing. They are 2" in diameter and constructed the same as the regular buoyancy arms. They range in size from 8" to 16" in 2" increments to be able to add just the amount of buoyancy you need to offset the weight of the housing and strobes or lights.

Arm Length

Amount of buoyancy per arm length

8" (DB-BL08)

4.5 oz

10" (DB-BL10)

8 oz

12" (DB-BL12)

11 oz

14" (DB-BL14

14.8 oz

16" (DB-BL16)

1 pound 2 oz.

It is important to weigh your whole system underwater. This can be done in a pool, large laundry tub, use rope to gather the whole set up together and then hang a scale from the rope, keeping the entire unit under the water. A luggage scale is perfect for this, just be careful not to get the scale itself wet. Once you know what it weighs then you can decide how much of that weight you would like to take off the system with the sections of the buoyancy arms listed above. Please call us to discuss results of the above tables and how they correlate to your weighed system. You might want to weigh your system with different lenses and ports for more accurate diving conditions.

Email (info@ulcs.com) for a copy of the 2" buoyancy arms weight and measurements chart.

With two arm lengths, 1 AC-CSB, 2 AC-CSF, and 1 strobe adapter and 1 base adapter these are the calculations: You will need to add in the weight of your strobes underwater to these calculations to get you to the buoyancy you need.

Arm lengths

Amount of Buoyancy with parts listed above

Two 8"

neutral

8" & 10"

1.75 oz

Two 10"

7 oz

10" & 12"

8.3 oz

Two 12"

11.2 oz

12" & 14"

15 oz.

Two 14"

1 pound 3 oz

14" & 16"

1 pound 6 oz

Two 16"

1 pound 9 oz.

The new style clamp (AC-CSB) is needed to put between the two new arms if you want the arms to come together when you are handling the whole system topside. This clamp weighs 1.3 oz more than the regular clamp. Salt water is approximately 1.026X more dense than fresh water. All these tests were done in fresh water.

Shows the size difference between the original buoyancy arms and the new ones and the old clamp and the new clamp

It is important to weigh your whole system underwater. This can be done in a pool, large laundry tub, use rope to gather the whole set up together and then hang a scale from the rope, keeping the entire unit under the water. The luggage scale we sell (on the what's new page) can be used for this weighing. Just be careful not to get the scale itself wet. Once you know what it weighs then you can decide how much of that weight you would like to take off the system with the sections of the buoyancy arms listed above. Please call us to discuss results of the above tables and how they correlate to your weighed system. You might want to weigh your system with different lenses and ports for more accurate diving conditions.

DB-EXT - Double ball Extension arms

Extends from 11" to 19"

Made in the USAPhone: 805.484.3334 - Fax: 805.984.3008Email: info@ulcs.com